In a turbomachine nozzle, a sector is a known part that comprises one or more vanes interconnecting two platforms. The nozzle is essentially constituted by uniting sectors to make up a ring. In the nozzle, each sector is positioned in or takes up an assembly position relative to the two sectors situated on either side thereof by means of contact surfaces of its platforms coming into abutment with contact surfaces of the platforms of the adjacent sectors.
In a nozzle, all of the sectors nearly always have the same shape. The differences between sectors are difficult to measure and are often not perceivable by the naked eye. A fortiori, in general the quality of the relative positioning between adjacent sectors is not evaluated. That is why it is not general practice to optimize the arrangement of sectors within a nozzle.
Nevertheless, it is found that as a result of variations in the conditions of fabrication and use of the sectors, there can exist non-negligible differences of shape between them. These differences can lead to the appearance of geometrical defects such as asymmetries, and that is very harmful for the lifetime of the nozzle or even of the turbomachine in which it is mounted, because of the vibration that such asymmetries can cause. Another harmful consequence is a decreasing the efficiency of the nozzle, or at least obtaining efficiency that is sub-optimal.